Building the same product with a different codebase is virtually guaranteed to be a disaster. This is the famous "second system effect."
Sometimes the original coders are the only people who know, not only how the software works, but even what it does. Unknown uses include features discovered by users but unknown to the makers, and one-off hacks created to serve a valuable customer.
> Building the same product with a different codebase is virtually guaranteed to be a disaster.
There is no point in going back and forth over this unless you have a real world example.
> This is the famous "second system effect."
[1] I believe you've misunderstood this effect. My understanding is that in the "second system effect", the succeeding system is not the "same" as the original
